P0420

Spooks

Hi all,

Tried to find my old thread about this but could find it so had to start a new one.

I've had the above fault code since i bought the car 18 months ago, after checking the exhaust for leaks etc i was certain it would be the O2 sensor, finally got round to replacing it at the weekend, reset the ecu with a code reader off e-bay (which I bought months ago). Have just got home from work and after about 31 miles the EML has come back on with the same code.

I bought the sensor from Autovaux, I'm assuming this would be ok (genuine)????

If so what else could it be? - I'm going to have another check of the exhaust manifold etc this weekend!

It's obviously been through an MOT since I've owned it so I guess if the cat was actually knackered it would have been picked up then? - I've also read (and not sure if true) that some non-genuine CAT's will trigger this fault????

Cheers yet again.

MikeS

means either your post cat sensor or your cat is buggered

unplug the sensor from its connector and give it a run

if you notice she is running a lot better then the chances are your cat has collapsed

little trick i picked up on google

Spooks

Cheers Mike,

Its a new sensor (post cat), and surely if the cat had collapsed it would have failed the MOT?

i'm gonna disconnect it tomorrow and give it a run over the weekend, but to be honest, it runs fine now with or without the light on, so not sure if I'll feel a difference but I'll give anything a go!!!!!

It lasted about 45 miles until the light came on this time, i know it sounds silly but i take it, it shouldn't need to bed in or something stupid?!!!!!

Will it kick up a fault code with the sensor not connected????

vocky

P0420 Catalyst System Low Efficiency

basically the lambda is telling the ecu that the cat isn't working properly, so either the lambda is duff or the cat is duff

Spooks

Ok cheers Guys,

Will start getting some pennies together!!